The present invention relates to ribavirin derivatives represented by the formula II, pharmaceutical compositions containing them as well as the use of the ribavirin derivatives represented by the formula II for the preparation of a medicament for the treatment of susceptible viral infections, for example, chronic hepatitis C infections administrating, the ribavirin derivatives being represented by formula II

Chronic infection with hepatitis C virus is an insidious and slow-progressing disease having a significant impact on the quality of life. It can eventually result in cirrhosis of the liver, decompensated liver disease and/or hepatocelluar carcinoma.
Combination treatment with interferon alfa-2b and ribavirin of patients with chronic hepatitis C is disclosed by Reichard et al. (The Lancet 1998; 351;83–87; and T. Poynard et al. (The Lancet, 1998, Vol. 352, October 31, p 1426–1432). See also J. G. McHutchinson et al. (N. Engl. J. Med., 1998, 339:1485–1492); and G. L. Davis et al. (N. Engl. J. Med., 1998, 339:1493–1499). However, this combination therapy is not always effective due to side effects associated ribavirin such as ribavirin-related hemolysis, and anemia.
There is a definite need for more potent, safer ribavirin derivatives having fewer side effects for use as monotherapy or in combination with antiviral agents, e.g., interferon-alpha, to treat patients having susceptible viral infections, e.g., chronic hepatitis C infections, in a long-term, effective manner.